Face seal for gas turbine engine

ABSTRACT

A face seal for a gas turbine engine comprises a seal body that has a contact face to engage a rotating surface. The contact face is defined as an area extending radially between an inner diameter of the seal body and an outer diameter of the seal body at one seal end providing a radial width. The radial width is between greater than 0.15 inch (3.81 mm).

This disclosure is a continuation-in-part application of U.S. Ser. No.12/015,715, filed on Jan. 17, 2008.

BACKGROUND OF THE INVENTION

This disclosure relates to a face seal for a gas turbine engine.

A face seal that is installed within an engine bearing compartmentextends between first and second seal end faces. One of the seal endfaces contacts a rotating seal face plate. The seal face plate ismounted for rotation with a rotor shaft. The end face that contacts theseal face plate is referred to as the “nose.”

Future aircraft engine products require cycles that have significantlyhigher rotor speeds than traditionally defined cycles. Higher rotorspeeds accordingly result in higher bearing compartment seal rubbingspeeds. Traditionally, to reduce friction and wear, the width of thenose has been minimized as much as possible. In one known configuration,the industry calls for nose widths to be 0.150 inches (0.381centimeters) or less.

In the past, improved carbon materials have been used to increase sealwear life. However, current carbon materials do not provide the desiredwear life for future higher rotor speed requirements.

Accordingly, there is a need to provide an improved face seal that canprovide a desired seal wear life at high rotor speeds, as well asaddressing the other short comings discussed above.

SUMMARY OF THE INVENTION

A face seal for a gas turbine engine comprises a seal body that has acontact face to engage a rotating surface. The contact face is definedas an area extending radially between an inner diameter of the seal bodyand an outer diameter of the seal body at one seal end providing aradial width. The radial width is greater than 0.15 inches (3.81 mm).

In one example, a seal face plate is supported for rotation relative toa non-rotating engine structure. The seal body has a central boreextending between first and second seal end faces. One of the first andsecond seal end faces comprises the contact face that engages the sealface plate. A resilient member exerts a load against the other of thefirst and second seal end faces to press the contact face against theseal face plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of this invention will becomeapparent to those skilled in the art from the following detaileddescription of the currently preferred embodiment. The drawings thataccompany the detailed description can be briefly described as follows.

FIG. 1 is a highly schematic view of a cross-section of a gas turbineengine.

FIG. 2 is a schematic view of a partial cross-section of a shaft,bearing, and face seal.

FIG. 3A is a cross-sectional view of an example face seal.

FIG. 3B is a magnified view of a portion of the example face seal asindicated in FIG. 3A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates selected portions of an example gas turbine engine10, such as a turbofan gas turbine engine used for propulsion. In thisexample, the turbine engine 10 is circumferentially disposed about anengine centerline 12. The turbine engine 10 includes a fan 14, acompressor section 16, a combustion section 18, and a turbine section20. The combustion section 18 and the turbine section 20 includecorresponding blades 22 and vanes 24. As is known, air compressed in thecompressor section 16 is mixed with fuel and burned in the combustionsection 18 to produce hot gasses that are expanded in the turbinesection 20.

FIG. 1 is a somewhat schematic presentation for illustrative purposesonly and is not a limitation on the disclosed examples. Additionally,there are various types of gas turbine engines, many of which couldbenefit from the examples disclosed herein and are not limited to thedesigns shown. For example, a gas turbine engine may contain a reductiongearbox disposed between the turbine section 20 and the fan 14, allowingthe fan 14 to turn at a different speed than the turbine.

FIG. 2 illustrates a rotating component 30 that is rotatable about anaxis defined by the engine centerline 12 (FIG. 1). A seal face plate 32also mounted for rotation about the axis. A bearing 34 supports therotating component 30 for rotation relative to a non-rotating enginestructure 36. The seal face plate 32 has a fore face 38 that engages aninner face 40 of the bearing 34 and an aft face 42 that faces a highpressure area 44 of the gas turbine engine 10.

An annular face seal 50 is positioned within this high pressure area 44and includes a first seal end face 52 that engages the aft face 42 ofthe seal face plate 32 and a second seal end face 54 that faces oppositeof the first seal end face 52. It should be understood that only theupper cross-section of bearing 34, seal face plate 32, and face seal 50are shown in FIG. 2, with the lower cross-section being similarlyconfigured to that of the upper cross-section as these components extendaround the axis.

The face seal 50 includes a seal body 56 with a central bore 58 thatsurrounds the axis. The face seal 50 is made from a carbon basedmaterial as known. The seal body 56 extends axially between the first 52and second 54 seal end faces in a direction that is generally parallelto the axis. A resilient member, such as a load spring 60 for example,is used to exert a spring force against the second seal end face 54. Theload spring 60 is supported by a non-rotating component 62 that has oneportion that is spaced axially aft of the second seal end face 54 andanother portion which extends into the central bore 58. The load spring60 applies an axial spring force to push the first seal end face 52 intodirect contact with the aft face 42 of the seal face plate 32.

As such, the first seal end face 52 comprises an annular contact face 68(FIG. 3) having a radial width W that engages a rotating component, i.e.the seal face plate 32. The contact face 68 is defined as a nose areaextending radially between an inner diameter D1 of the seal body 56 andan outer diameter D2 of the seal body 56.

In one example, a ratio of the outer diameter D2 to the inner diameterD1 is at least 1.054. In another example, the ratio is greater than1.060. In yet another example, the ratio is between 1.060 and 1.071.

In one example, the inner diameter D1 of the seal body 56 is less than5.734 inches (14.564 centimeters) and the outer diameter is greater than6.038 inches (15.337 centimeters). In another example, the width W ofthe annular contact face is greater than 0.15 inch (3.81 mm). In oneexample, the width W is approximately 0.25 inch (6.35 mm). In oneexample, the width W is approximately 0.20 inch. In one example, thewidth W is approximately 0.30 inch. As such, the contact area betweenthe face seal 50 and the seal face plate 32 has increased up to at least50% compared to prior configurations. This contact area increase ofapproximately 50% impacts the tribology of corresponding mating surfacesof the face seal 50 and the seal face plate 32 such that the resultingcarbon wear performance is greatly improved by providing a significantreduction in the seal face wear rate. A significant increase in sealwear life is provided with minimal cost impact.

Although a combination of features is shown in the illustrated examples,not all of them need to be combined to realize the benefits of variousembodiments of this disclosure. In other words, a system designedaccording to an embodiment of this disclosure will not necessarilyinclude all of the features shown in any one of the Figures or all ofthe portions schematically shown in the Figures. Moreover, selectedfeatures of one example embodiment may be combined with selectedfeatures of other example embodiments.

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthe essence of this disclosure. The scope of legal protection given tothis disclosure can only be determined by studying the following claims.

1. A face seal for a gas turbine engine comprising: a seal body havingan annular contact face arranged about an axis and configured to engagea rotating surface wherein the contact face defines a radial width ofthe annular contact face extending radially between an inner diameter ofthe seal body and an outer diameter of the seal body at one seal end,wherein the radial width is greater than 0.15 inch (3.81 mm) andapproximately 0.30 inch (7.62 mm), and a ratio of the outer diameter tothe inner diameter is between 1.054-1.071.
 2. The face seal according toclaim 1 wherein the radial width is approximately 0.20 inch (5.08 mm).3. The face seal according to claim 1 wherein the radial width isapproximately 0.30 inch (7.62 mm).
 4. The face seal according to claim 1wherein the radial width is approximately 0.25 inch (6.35 mm).
 5. Theface seal according to claim 1 wherein the seal body is comprised of acarbon based material.
 6. The face seal according to claim 1, whereinthe inner diameter is less than 5.734 inches (14.564 cm), and the outerdiameter is greater than 6.038 inches (15.337 cm).
 7. A face sealassembly for a gas turbine engine comprising: a seal face platesupported for rotation relative to a non-rotating engine structure; aseal body having a central bore extend between first and second seal endfaces wherein one of the first and the second seal end faces comprisesan annular contact face that engages said seal face plate, with theannular contact face defines a radial width of the annular contact faceextending radially between an inner diameter of the seal body and anouter diameter of the seal body, and wherein the radial width is greaterthan 0.15 inch (3.81 mm) and approximately 0.30 inch (7.62 mm), a ratioof the outer diameter to the inner diameter is between 1.054-1.071; anda resilient member exerting a load against the other of the first andsecond seal end faces to press the contact face against the seal faceplate.
 8. The face seal assembly according to claim 7 wherein the radialwidth is approximately 0.20 inch (5.08 mm).
 9. The face seal assemblyaccording to claim 7 wherein the radial width is approximately 0.30 inch(7.62 mm).
 10. The face seal assembly according to claim 7 wherein theradial width is approximately 0.25 inch (6.35 mm).
 11. The face sealassembly according to claim 7 wherein said seal body is comprised of acarbon based material.
 12. The face seal assembly according to claim 7,wherein the inner diameter is less than 5.734 inches (14.564 cm), andthe outer diameter is greater than 6.038 inches (15.337 cm).